Trunk circuits



Dec. 22, 925- 1,566,345

I G. H. PETERSON TRUNK CIRCUI T 5 Filed Sept. 23. 192.4

a m g;

Patented Dec. 2 2, 1925.

UNITEDJSTATES- PATENT. OFFICE.

GEORGE H- rE esQa Be QKL Ni NEW ear; A$INB r0 AMERICAN TELE- ore AND sme e s coa ser, A CORPQBATION ew u TRUNK. CIRCUIT.

Application filed September 23, 1924. Serial No. 739,396.

To allwhom it may concern;

Beit known that I, Gnome Pn rnnson, residing at Brooklyn, in the countyof Kings and State of New York, have invented certain Improvements inTrunk Cir: cuits, of which the following is a Speciifi; cation.

This invention relates to telephone exchange systems inwhich connecting.QPBI? ators are employed for extending connections, with indicatingmechanisms at such operators positions to identify the designations ofdesired lines.

The invention is shown as applied to a system employing automatic switchmechanisms for extending calling subscribers lines to tandem operatorspositions, which are provided with indicating apparatus for registeringthe numbers of wanted lines. Tandem operators at these positions trunkthe calls 'to completing operators at exchanges in which the desiredlines are located.

In trunking a call, the tandem operator plugs the incoming end of thecalling trunk into an idle trunk out oing to the desired exchange andgives the l3 operator the number displayed by the incoming apparatus ather position, whereupon the B operator completes the call in the usualmanner.

The principal feature of the invention is the provision of means forautomatically splitting the calling trunk when it is plugged up to anoutgoingtrunk and for connecting the tandem operators telephone set tothatportion connected to the outgoing trunk whereby thetandemopcrator isen:

- abled to converse with the B operator without the calling subscriberhearing the, con: versatio-n. The tandem operators telephone set isafterward disconnected from the trunk and the talking circuit completedso as to allow the calling subscriher'to converse with the calledsubscriber Other features of the invention will he pointed out in thedetailed description to follow.

The invention is illustrated; in the accompanying drawing wherein thesubscribers station X in addition to being provided with the usualsubrstation apparatus is also provided with an impulse sending device Y.The subscribers line is automatically connected to a tandem operatorsposition shown between the broken vertical lines by operated byimpulsesv transmitted from the sender Q in which is stored up theimpulses transmitted by the sending device Y at the subscribers stationThe automatic switches N, sender Q and the display board equipment andcircuits are fully disclosed in the patent to A. E. Lundell and E. H.Clark 1,46%,084; and will therefore not be described in detail in thisspecification. Y

The B operators telephone set and app atu s own in e outline 1.00 isfully s losed in a copending application S. N. 7 3 fi ed ept 8, 1 24, int e names of B nd 3- Bailey and Edgar P. Broe to th s me assign e es ithe pres nt applica ion, The operation of the system is as follows: Thesender Q, is automatically connected to the subscribers line upon theinitiation o a call eupon th connection is ex-. t nded to the andemoperators trunk Tl? which terminates in h p ug. 3.3- h th 1 call isextended to the sender Q the-sub,- s iber man pula ing th send ng eviceY nsm ts impu se corre ponding to h number of the wanted line. arereceived by and stored upon the sender Q- When the c nne t on i 'extened to he t nk, the c u t f relay A s omp e d Thes pu s by a c o u of thc u i h au matic I equipment. The operation of relay A comp t s h i uitof r lay B as o l ws:

und, ontac of relay A, con a of relay D, 2, winding of relay B, 3, 1,contacts o lay K, b tery t ground The pe tion of relay B completes thecircuit of lamp es ollows; gro nd, c n a s o ay r ista e 4 amp L,battery to gr A t ay B pe te it locks to ba te y through its owncontact.

The lighting of the lamp L notifies the tand m ope r of a al wher up shdepresses the display button M which closes the circuit of relay I asfollows: ground at Z, 6, contacts of key M, 7, contacts of relay B, 18,winding 31 of relay I, 17, contacts of relay H, 16 to battery at Z.Relay 1 in operating locks to ground through its windings 3) and 31under control of relay H and prepares a circuit for operating relay Rand also completes the circuit of relay K. The operation of relay Kcompletes the circuit of relay (1 follows: ground, battery, contacts ofrelay B, 3, contacts of relay K, 9, winning of relay 6, to ground. Theop eration of relay G extends battery to conductor 10 extending to thewinding of relay D, but as the other terminal of the winding D islikewise connected to battery it fails to operate at this time. Theoperation of relay C completes the circuit of relay R as follows:ground, battery, contacts of relay C, 25, winding of relay R, 14,contacts of relay 1, 15 to ground at Z. The operation of relay R seversthe trunk conductors and connects the sender Q to the display board Z,thereby causing the operation of the sender which transmits thestored-up impulses which operate the indicators to display be fore thetandem operator the number of the wanted line.

The operation of relay it opens the circuit of relay A by disconnectingit from the calling line. Relay A upon restoring removes ground from thewinding of relay B allowing it also to restore.

Relay B in restoring removes battery from the circuit which originallyoperated relay G. Relay C however remains operated as its circuit iscompleted through the winding of relay D, as follows: ground, winding ofrelay C, contacts of relay C, 10, winding of relay D, battery to ground.Relay D operates at this time thereby preparing an energizing circuitfor relay G. I

The operation of relay K and the release of relay B connects lamp Lthrough interrupter 50 to ground thus causing the lamp L to flash,indicating to the operator that the display button has been operated andthat the connection is extended to the trunk.

After the codeimpulses have all been received, ground is removed fromconductor 15 at the display board Z, thereby opening the circuit ofrelay ft whch restores and disconnects the trunk conductors from thedisplay board and connects them through to the conductors 40 and 41.

When relay It restores, assuming the calling subscribers receiver isstill off the hook, relay A is again energized over the calling trunk.The operation of relay A at this time connects ground over conductor 1the right hand inner contacts of relay D, conductor 10, and contacts ofrelay C to the winding of relay C, thereby shunting it and causing it torestore. Relay D does not restore, however, as it'is locked through itsinner right hand contacts to the ground supplied by relay A. andtherefore is under control of relay A. Relay C in restoring closes itsright hand back contacts thereby shunting lamp P with resistance 36 andpreventing its illumination when plug 33 is inserted in the outgoingtrunk.

The tandem operator upon perceiving the number of the wanted line testsfor an idle trunk extending to an exchange in which the wanted line islocated. Assuming that the trunk terminating in jack 34 is idle the plug33 is inserted into the jack thereby completing the circuit of relay Eas follows: ground, sleeve circuit of jack 34 including sleeve relay 35,sleeve of plug 33, winding of relay E, to battery to ground throughlampl and resistance 36 in parallel, it being remembered that relay C isreleased and relay D operated at this time. Before the operation ofrelay E, battery was connected through its contacts to coir ductor 12,and thence through the contacts of relay H to the winding of relay G,thereby shunting Upon the operation of relay E, this shunt is removedand relay G operates in the previously prepared circuit.

The operation of relay D also connected the winding of polarized relay Tto the talking conductor 41, thusestablishing a bridge across conductors40 and 41 including the windings of relay T and impedance coil S.

The operation of relays E and D allows the circuit of relay Gto becompleted as follows: ground, contacts of relay D, 13, resistance 0, 12,contactsof relay H, 11, winding of relay G, battery to ground.

The operation of relay G severs the trunk conductors and connects theoperators telephone set to conductors 40 and 41, allowing the operatorto converse with the operator at the exchange wherein the called line islocated but prevents the calling subscriber from hearing thisconversation.

After the tandem operator gives the B completing operator the number ofthe wanted line, she depresses release button W, which completes thecircuit of relay H, as follows: ground, contacts of button WV, 37,contacts of relay G, 38, winding of relay H, battery to ground. Whenrelay H operates it looks to ground through contacts of relay D asfollows: ground, contacts of relay D, 13, resistance 0, 12, contacts ofrelay H, winding of relay H, battery to ground.

The operation of relay H breaks the circuit of relay I causing it torestore. The restoration of relay 1, opens the circuit of relay K,allowing it to restore and open the flashing circuit for the lamp L.

Relay H in operating opens the circuit of relay G which releases anddisconnects the operators telephone from the plug end of the trunk andcloses the trunk conductors through.

The polarized relay Tis operated over the trunk from the B operatorsposition when the called party answers and when so operated causes theoperation of relay U which connects the windings of relay A, in reverseorder to the talking conductor, extending to the calling line so as toreverse battery therein for the purpose of operating the chargingapparatus in the automatic oflice N. 7

When the calling subscriber replaces the receiver relay A becomes(lo-energized and upon restoring removes ground from the locking contactof relay D.

Relay D restoring removes battery from the coil 36 which shunted lamp P,thereby causing the lamp to light, opens the circuit of relay H causingit to restore and also removes relay T from across the trunk to give adisconnect signalto the distant B completing operator. Upon observingthe lighting of lamp P the tandem operator removes the plug 33 from thejack 34- thereby releasing relay E.

Relays E and Hin restoring replace the battery shunt to the G relaypreventing its operation in the handling of a succeeding call asheretofore described.

Relay I may also be restored for the purpose of wiping out the displayednumber in case the tandem operator presses a second display key to bringin another number before she depresses the release key associated withthe first trunk.

that is claimed is:

1. In a telephone exchange system, the combination of atrunkcircuitterminating in a plug, an operators telephone set, and meansautomatically responsive to the insertion of said plug into an outgoingline jack for disconnecting the plug from the talking conductors of saidtrunk and for connecting the operators telephone set to said plug.

2. In a telephone exchange system, the combination of a call indicatortrunk terminating in a plug, an operators telephone set, a relay, atrunk jack, means controlled by said relay when said plug is placed insaid jack for disconnecting the talking conductors of said trunkfrom'the plug and connecting said telephone set to said plug,

a key, and means controlled by said key for,

releasing said relay to disconnect said operators telephone set fromsaid plug and to reconnect said trunk conductors thereto.

3. In a telephone exchange. system, the

combination of -an operators position a trunk terminating at theoutgoing end in an automatic switch and at the incoming end in a plug atsaid operators position, an indicator and a display key at saidposition,

means controlled by said key for causing said indicator to be'connectedto sald trunk, a relay, an outgoing trunk from said posi- 'tion and atrunk jack therefor, means for causing the operation of said relay whensaid key is operated and the plug is placed in the trunk jack, todisconnect said incoming trunk from said outgoing trunk and to connectsaid operators telephone set to said outgoing trunk, a release key, andmeans controlled thereby for causing said operators telephone set to bedisconnected from said trunk. r

4. In a telephone exchange system, the combination of an operatorsposition, a

trunk terminating at its outgoing end in an automatic switch and atitslncomlng end in a plug at said positlon, an lndicator associated withthe incoming end of said trunk, an operators telephone set, a relay,

an outgoing trunk jack'atv said position,

connection of the operators telephone set from said outgoing trunk jackand the closing of the incoming end of said trunk.

5. In a telephone exchange system, the combination of an incoming trunkcircuit terminating at'an operators position in a plug, an outgoingtrunk jack thereat, a relay arranged to be operated when the plug isplaced in the trunk jack, a second relay, an operators telephone set atsaid position, means controlled by the first relay for causing theoperation of the second relay to disconnect the incoming trunk from theoutgoing jack and connect the operators telephone set to the outgoingtrunk, a key, and means controlled by said key for releasing the secondrelay to disconnect the operators telephone set from said outgoingtrunk, and to reconnect said incoming trunk to said trunk ack.

6. In a telephone exchange system, the combination of a trunk circuitterminating at an operators position in a plug, an indicator and adisplay key thereat, means controlled by said display key for connectingsaid indicator to said trunk, a control relay, an operators telephoneset, a trunk jack, and means for causing the operation of said controlrelay when said plug is placed in said jack after said display key isoperated for connecting the operators telephone set to said trunk ackand for disconnecting said trunk from said ack.

7. In a telephone exchange system, the combination of a trunk circuitterminating at one end in a plug, anindicator and a display key, meanscontrolled by said display key for connecting said indicator to saidtrunk circuit, a control relay, an operators telephone set, a trunkjack, means for causing the operation of said control relay when saidplug is placed in said jack for connecting the operators telephone setto said trunk jack and for disconnecting said trunk from said jack, arelease key, and means controlled by said release key for releasing saidcontrol relay to disconnect the telephone set from the trunk jack.

8. In a telephone exchange system, the combination of a trunk circuitterminating at one end in a plug, an indicator and a display key, meanscontrolled by said display key for connecting said indicator to saidtrunk and for preparing a circuit to control the opening of the trunkconductors a control relay in said control circuit, an operatorstelephone set, a trunk ack, means for causing the operation of saidcontrol relay when said plug is placed in said ack for connecting theoperators telephone set to said trunk: plug and for opening the trunkconductors, a release key, and means controlled by said release key forreleasing said control relay to disconnect said operators telephone setand to close the conductors of said trunk.

9. In a telephone exchange system, the combination of a subscribersstation provided with a sending device, a trunk circuit, automaticswitching mechanism for connecting said subscribers line with said trunkcircuit, a sender associated with said switching mechanism responsive tothe impulses transmitted by said sending device and for storing saidimpulses, an indicator associated with said trunk, a display key, meanscontrolled by said key for connecting said sender to said indicator forregistering thereon the impulses stored by said sender, a plug,associated with said trunk and a co-operating outgoing trunk jack, acontrol relay in said trunk circuit, an operators telephone set, andmeans for operating said control relay when the display key is operatedand the plug is placed in the jack for connecting the operatorstelephone set to said trunk jack and for disconnecting the subscribersstation.

10. In a telephone exchange system, the combination of a subscribersstation provided with a sending device, a trunk circuit, automaticswitching mechanism for connecting said subscribers line with said trunkcircuit, a sender associated with said switching mechanism responsive tothe impulses transmitted by said sending device and for storing saidimpulses, an indicator associated with said trunk, a display key, meanscontrolled by said display key for connect ing said sender to saidindicator for registering thereon the impulses stored by said sender, aplug associated with said trunk and a co-operating outgoing trunk jack,a control relay in said trunk circuit, an operators telephone set, meansfor operating said control relay when the display key is Operated andthe plug is placed in the jack for connecting the operators telephoneset to said outgoing trunk jack and for disconnecting the subscribersstation from the plug, a release key and means controlled thereby forrestoring said control relay to disconnect the operators telephone setfrom said "trunk jack and to reconnect the subscribers station to theplug.

11. In a telephone exchange system, a trunk circuit terminating at oneend in a plug, an outgoing trunk jack, a control relay associated withsaid trunk circuit adapted when operated to disconnect said trunkcircuit from said plug and to connect an operators telephone thereto, asecond relay, means controlled by said second relay for shunting saidcontrol relay when the second relay is in a de-energized condition, andmeans for operating said second relay when the p t is placed in saidjack, the operation of said relay remo ing the shunt from said controlrelay and allowing it to operate.

In a telephone exchange system, a trunk circuit terminating at one endin a plug, an outgoing trunk jack, a control rclay associated with saidtrunk circuit adapted when operated to disconnect said trunl' circuitfrom said plug, a second relay, means controlled by said second relayfor shunting said control relay when the second relay is in atie-energized condition, and means for operating said second relay whenthe plug is placed in said jack, to remove the shunt from said controlrelay thereby allowing it to operate.

13. In a telephone exchange system, a trunk circuit terminating at oneend in a plug, an operators telephone, a trunk jack, a control relayassociated with said trunk circuit, a second relay, means controlled bysaid second relay for shunting said control relay when the second relayis in a de-energized condition, means for operating said second relaywhen the plug is placed in said jack, the operation of saidrelayremoving the shunt from said control relay allowing it to operate,the operation of said control relay serving to connect said opcratorstelephone to said trunk ack, a release key, and means controlled by saidrelease key for causing said control relay to restore therebydisconnecting the operators telephone set from said trunk ack.

14. In a telephone exchange system, the combination of a trunk circuit,the incoming end being provided with an indicator and a plug, anoperators telephone set, a control relay, an outgoing trunk circuit, andmeans for operating said control relay when said plug is associated withsaid outgoing trunk circuit for connecting the operators telephoneset tothe outgoing trunk circuit,-

combination of a trunk circuit, the incoming end being provided with-anindicator and a plug, a display key, means controlled by said displaykey for causing said indicator to be" connected to said trunk, a controlrelay, an operators telephone set, an outgoing trunk circuit, means foroperating said control relay when said plug is associated with theoutgoing trunk after the display key has been actuated, the operation ofsaid control relay serving to connect the operators telephone set to theoutgoing trunk circuit and for opening the incoming end of said trunk, arelease key, and means controlled by said release key for restoring saidcontrol relay to disconnect the operators telephone set and to close theincoming end of said trunk.

16. In a telephone exchange system, the combination of a trunk circuitprovided with a control relay, an operators telephone set, a secondrelay which in its de-energized condition shunts said control relay, andmeans for operating said second relay for removing the shunt from saidcontrol relay, the removal of said shunt serving to allow the operationof said control relay to split said trunk circuit and to connect theoperators telephone set to one portion thereof.

17. In a telephone exchange system, the combination of a trunk circuitprovided with a control relay, an operators telephone set, a secondrelay which in its de-energized condition shunts said control relay,means for operating said second relay for removing the shunt from saidcontrol relay, the removal of said shunt serving to allow the operationof said control relay to split said trunk circuit and to connect theoperators telephone set to one portion thereof, a release key, and meanscontrolled by said release key for restoring said control relay todisconnect the operators telephone and to reconnect said trunk portions.

18. In a telephone exchange system, an operators position, an-operatorstelephone circuit therefor, a first trunk circuit incoming to saidposition, means for extending a connection to the operators positionover said trunk, an indicating device at said position, means controlled,at said position for associating said indicating device with saidtrunk, a second trunk circuit for extending said first trunk circuit andmeans jointly responsive to the extension of said first trunk to saidsecond trunk and the operation of said controlled means to open thetalking circuit between said first andsecond trunks and to connect saidoperators telephone to said second trunk.

19. In a telephone exchange system, an

operators position, anoperators telephone circuit therefor, a trunkcircuit incoming to said position, means for extending a connection tosaid operators position over said trunk, an indicating device at saidposition, an assignment key controlled at said position for associatingsaid indicating device with aid trunk, a' second trunk circuit outgoingfrom" said position, means for associating said incoming trunk circuitwith said outgoing trunk circuit for extending a connection thereover,means jointly responsive to the actuation of said assignment key and theextension of said incoming trunk circuit to said outgoing trunk circuitto open the talking circuit between said incoming and going trunkcircuits and to connect said operators telephone with said outgoingtrunk circuit, and a release key at said position adapted when operatedto disconnect said operators telephone and to reclose said talkingconnection between said incoming and outgoing trunk circuits.

20. In a telephone exchange system, the combination of a trunk circuitterminating in a plug, an operators telephone set, and a relayautomatically responsive to the insertion of said plug into an outgoingline jack for disconnecting the plug from the talking conductors of saidtrunk and for connecting the operators telephone set to said plug.

21. In a telephone trunking system, an incoming trunk operatorsposition, a trunk circuit terminating thereat in a plug, an outgoingline jack thereat, means located at said position and adapted to beassociated with said trunk circuit for indicating the number of a wantedline, means associated with said trunk for associating said indicatingmeans therewith, an operators telephone set at said position, and othermeans automatically responsive to the insertion of said plug into saidoutgoing line jack for disconnecting the plug from the talkingconductors of said trunk and for connecting the operators' telephone setto said plug.

22. In a telephone trunking system, an incoming trunk operatorsposition, a trunk circuit terminating thereat in a plug, an outgoingline jack thereat, means located at said position and adapted to beassociated with said trunk circuit for indicating the number of a wantedline, means associated with said trunk for associating said indicatingmeans therewith, an operators telephone set at said position, and arelay automatically responsive to the insertion of said plug into saidoutgoing line jack for disconnecting the plug from the talkingconductors ofv said trunk and for connecting the operators telephone setto said plug.

23. In a telephone trunking system, an

incoming trunk operators position, a trunk circuit terminating thereatin a plug, an outsaid outsaid indicating means with said trunk for 10disconnecting the plug from the talking conductors of said trunk and forconnecting the operators telephone set to said plug.

In testimony whereof, I have signed my name to this specification this20th day of 15 September, 1924.

GEORGE H. PETERSON.

